In connection with an aircraft engine, labyrinth seals are used to seal off cavities of higher and lower pressures in areas where there is relative rotational motion. Referring to FIG. 2A, a labyrinth seal 200 in accordance with the prior art is shown.
The seal 200 includes knife edges 201 that are used to create the sealing. The edges 201 rub against a variety of materials and may vary in terms of size, shape, count, angle, orientation, height, and width.
The seal 200 includes attachment lands 202a and 202b. The land 202a is forward of the land 202b. One or both of the lands 202a and 202b can be a tight or snap fit. The snaps can be scalloped to allow air flow through the snap.
The seal 200 includes segments 203a, 203b, and 203c (which, when taken collectively, are referred to as the barrel 203 herein). The barrel 203 extends from the forward attachment land 202-a in the aft direction.
The seal 200 includes a hammerhead 204. The hammerhead 204 may have multiple uses but in the context of this disclosure the hammerhead 204 is used to create a(nother) sealing cavity.
The seal 200 includes tabs 205. The tabs 205 are used to prevent rotation, thereby serving as an anti-rotation mechanism.
The seal 200 is subjected to stress and large thermal gradients when placed into operational use, leading to component fatigue and a reduction in terms of component lifetime. Such stress may be a result of the lands 202a and 202b being coupled to a large material mass (e.g., a disc—not shown in FIG. 2B), whereas the barrel 203 may be composed of a thin mass of material that interfaces to a hot airflow associated with a gas path. The large material mass/discs operate at a cooler temperature than the seal 200, and thus, do not grow as much as the seal 200 in a radially outboard direction (see the radial reference direction superimposed in FIG. 2A). Consequently, the barrel 203 may be compelled to deflect in the radial reference direction. The deflections could be large, potentially causing the barrel 203 to crack.